Drive means



W. P. RYAN July 23, 1963 DRIVE MEANS 2 Sheets-Sheet 1 Filed Oct. 20, 1960 INVENTOR WILLIAM E W. P. RYAN DRIVE MEANS July 23, 1963 Filed Oct. 20, 1960 2 Sheets-Sheet 2 REVERSE FORWTRD 4 5 6 5 5 5 j\.l|| GM T E G R NS M wmom E m m. nmmw m Wm P A E m Wu 0 H RM C Fig.4

INVENTOR WILLIAM R RY ATTORNEYS United States Patent 3,698,398 DRIVE MEAN William P. Ryan, Avon, Conn, assignor to Royal McBee Corporation, Port Chester, N.Y., a corporation of New York Filed Oct. 20, 1960, Ser. No. 63,916 11 Claims. {CL 74321) This invention relates to a novel drive means for selectively displacing an output member through predetermined variable distances; more particularly the invention relates to an improved drive arrangement for cyclically positioning an output shaft at successively different angular positions.

In matrix type printing devices, and similar devices, a printing head must be successively oriented in different positions in order that a desired sequence of characters may be printed. Here for each printing cycle it is necessary to provide a means for driving the matrix head from a normal rest to a prescribed displaced printing position and then back to said normal position. This action requires the use of a very efficient drive mechanism.

One object of the invention is toprovide a relatively simple drive mechanism which is fast acting and has low static and dynamic inertia.

Another object of the invention is to provide a manually or automatically controllable drive means for cycli cally indexing an output shaft whereby a driven member, such as a matrix printing head, may be successively displaced to different predetermined operative positions.

Another object of the invention is to provide a novel positioning drive mechanism whereby a plurality of cyclically operated control means determine the period during which a driven member is operatively coupled to a driving means.

A further object of the invention is to provide a novel cyclically operated positioning drive mechanism whereby a driven member may be rapidly displaced from a normal position to any one of several operative positions and then back to said normal position, the extent of said displacements of said driven member being determined by the selective operation of a plurality of switches.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIGURE 1 is a schematic plan view of the instant mechanism.

FIGURE 2 is a perspective view illustrating the cam and switching arrangement in the instant apparatus.

FIGURE 3 is a side elevational view taken in partial section of a portion of the apparatus shown in FIG- URE 2.

FIGURE 4 shows a typical timing diagram for the instant mechanism.

Unless otherwise indicated it will be understood that the various hereinafter described parts are suitably supported on a machine frame in a well known manner.

Referring to FIGURE 1 there is shown a first drive shaft and a second drive shaft 11 to which are respectively fixed gears 12 and 13, both of said gears meshing with a central gear 15 that is rotatably driven at a predetermined speed by any suitable means such as a motor 16. The drive shaft 11 is adapted to be operatively coupled to an intermediate driven shaft 17 by means of a conventional type wrap spring clutch arrangement generally indicated at 20. The operation of the clutch 20 is controlled in a well known manner by a detent tip 21 on the armature 2.2 'of a voice coil or solenoid 23. It will be "ice understood that when the armature of the normally deenergized voice coil is in its normal position the spring clutch is in its disengaged condition and that when said voice coil is energized the clutch 20 will be in its engaged condition. The voice coil 23 and wrap spring clutch 20 have a very short response time.

R otatably secured and axially slidably mounted on the intermediate driven shaft 17 is a reversible gear means comprising a collar 24 formed with two opposed and coaxial bevel gears 25 and 26. The collar 24 is axially shiftable so as to alternately mesh gears 25 and 26 with a gear 27 which is fixed on a rotatably mounted output shaft 36. The shaft 30 is connected through suitable gearing 31 etc, to a rotatably indexible matrix printing head 32 which is adapted to cooperate with a printing hammer 33. The shifting movement of collar 24 is produced by a lever 34 which is pivoted on stud 35 and which is provided at one end with a pin 36 that rides in the central annular peripheral collar groove 37 and at the other end with a pin 38 that engages the walls of a slot 39 formed in the end of a cam follower arm 40. The arm 40 is pivotally mounted on a stud 41 and is provided at its upper end with a rotatable follower roll 42 that is urged by means of a spring 43 into operative engagement with the lateral camming face of a drive reversing cam 44 that is fixed to a control shaft 45. The control shaft 45 is adapted to be coupled with said first drive shaft 10 through a conventional type one revolution clutch 46. A rotational displacement of shaft 10 will, through cam 44, spring 43, and levers 40 and 34, serve to axially shift collar 24 so as to alternately connect the gears 25 and 26 to the gear 27, this action serving to condition the gearing so that the :output shaft 30 may be driven in both rotational directions.

The control shaft 45 has secured thereto five axially spaced timing cams 47, 48, 49, and 51 which are adapted to respectively cooperate with the electrical switches 52, 53, 54, 55 and 56. These switches are selectively conditionable to be operated by said timing cams so as to control the time duration of flow of electrical current from a source to said voice coil or solenoid through suitable wiring '57 and 60. In that the angular speed of drive shaft 11 is fixed relative to that of control shaft 45 the variable extent of angular displacement for the output shaft 30 may be determined by correspondingly controlling, through said timing cams, the time duration for retaining the clutch 20 in the engaged condition.

Referring to FIGURES 2 and 3 the structural arrangement for the timing cams and related equipment is shown. Here, in that each cam and related switch arrangement is constructed and operated in a similar manner explanation of one thereof will sufiice here. The switch 56 comprises a pair of contact arms 62 and 63, FIGURE 3, having lower ends which are fixed to a common base 64 and having mutually engageable electrical contacts 65a and 65 respectively formed thereon. The arm 63 is formed with an arcuate tip 66 which is adapted to be engaged and moved to the left, FIGURE 3, by each of the two identically shaped lobes 67 and 68 formed on the timing cam 51. The upper end of the other switch contact arm 62 is provided with a hooked portion 69 which is adapted to be displaced to the right, FIGURE 3, and into latching engagement with the adjacent hooked edge 70 :of a flexible latch 71 that is fixed at one end to the stationary cross shaft 72. The free end of the flexible latch 71 is yieldably biased into normal engagement with a stationary cross shaft 73. To the upper end of the switch contact arm 62 there is secured a cable 78 which when pulled will move the yieldable contact arm 62 from its normal FIGURE 3 position into latching relation with the hooked edge of the latch 71. Corresponding cables 74, 75, 76 and 77, FIG- URE 2, are provided for switches 52, 53, 54 and 55 respecacaaaaa tively. Means are provided for unlatching all the switch contact arms such as 62, such means comprising a rod or shaft 81, FIGURE 2, which underlies the various switch latches such as 71 and which is secured to the free ends of the bail arms 82 and 83 that are fixed to the rotatably mounted cross shaft 84. Rotatably mounted on the inside face of bail arm 83 is a cam follower 85 which cooperates with the periphery of a cam 86 secured to said control shaft 45. As will be apparent when control shaft 45 rotates the bail arms 82 and 83 and the cross rod 81 will be elevated thereby lifting the latches 71 so as to permit the latched switch contact arms, such as 62, to be restored to their normal positions. When these switch contact arms are in such normal positions, rotation of the various timing cams will not displace the contact arms such as 63 sufficiently far to the left, FIGURE 3, so as to cause engagement of the electrical switch contacts such as 65 and 65a. When however any of the switch contact arms are moved to latched condition as above described, the camming of the related switch arms, such as 63, by said timing cams 4751 respectively will serve to engage the respectively related contacts such as 65 and 65a. The rotative phase, and in some cases the peripheral length, of the lobes formed on the respective cams will serve to serially operate the associated switches 5256, for differing lengths of time. The timing diagram of FIGURE 4 illustrates the respective lengths of time and the respective phase relation between the closures of each of the switches 52-56, assuming of course that each of these switches have been conditioned for operation by cables 74--78 respectively.

The instant apparatus is cyclically actuated by initiating an operation of the one revolution clutch 46, FIGURE 1. The means for initiating the operation of this clutch comprises a lever 90, FIGURE 2, which is normally biased into engagement with the stop 92 by means of a spring 93. A cable 94 secured to the upper end of said lever 90 enables the latter to be pivotally displaced so that its detent edge 95 swings out of operative engagement with a control lug 96 of the one revolution clutch. This action enables the drive shaft to rotate the control shaft 45 through 360 degrees in a well known manner.

If desired, the cables 74, 75, 76, 77 and 78 may be selectively actuated by means corresponding to the cables 36, etc., shown and described in copending application Serial No. 4,749, filed January 26, 1960, for Keyboard Control and Actuating Device. The instant cable 94 which is actuated to initiate each cyclic operation of the instant drive mechanism would correspond here to cable 65 of said copending application.

In the operation of the instant mechanism a coded combination of the various cables 74, 75, 76, 77 and 78 are pulled so as to move the related switch contact arms into latching engagement with the switch latches thereby conditioning these selected switches for operation by the respectively associated timing cams. After this switch conditioning operation is completed the cable 94 is pulled thereby initiating a single revolution of the control shaft 45. During the rotation of the timing cams 47-51 the various switches 52-56 which have been conditioned for operation will be closed by the first lobe on the related timing cams and current will be permitted to flow through the solenoid 23 for a predetermined period. Any coded combinations of switche that are conditioned for operation are preferably such as to initiate a control current that is continuous rather than intermittent. During this period the clutch will be in the engaged condition thereby permitting drive shaft 11 to rotate the output shaft through a predetermined angular displacement. During the first 180 degrees rotation of the control shaft the output shaft will complete its forward rotative displacement so as to locate said matrix printing head 32 at a predetermined position so that the printing hammer 33 may thereafter be actuated to print a desired character on a record sheet in a well known manner; the timing of the hammer operation being illustrated in FIGURE 4. During the second half cycle, or the last degrees of rotation of the control shaft 45, the cam 44- will first shift the collar 24 so as to reverse the direction of drive of output shaft 30 as illustrated in the timing diagram. Thereafter the clutch 20 is again energized, due to the operation of the second lobe on each of the said related timing cams, for the same time period as during the first 180 degrees of control shaft rotation. In this way the output shaft 30 will be rotated in a reverse direction back to its normal position before completion of the single revolution of the control shaft 45. Just before completion of the cyclic rotation of the control shaft the cam 44 will restore the reversible gearing to normal condition as illustrated in FIGURE 4 and the rotating cam 86 Will lift the switch latches and release the selected switch contact arms for movement back to their respective inoperative positions, such as illustrated for contact arm 62 in FIGURE 3. The apparatus will then be ready for the neXt cyclic operation.

As may be readily appreciated the instant drive mechanism rotates the output shaft 39 through equal forward and reverse strokes during each cycle of operation of the mechanism, the successive cycles serving to respectively displace the said output shaft and matrix printing head to variable desired extents so that diiferent characters may be printed on the record sheet. This drive mechanism is capable of eflicient high speed operation without interference from inertia forces and vibrations.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration only and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

The invention claimed is:

l. A drive mechanism; comprising a drive shaft, an

output shaft, clutch means operable to couple said drive and output shafts, a control shaft, means for driving said control and drive shafts, means operated in timed relation to the rotation of said control shaft for maintaining said clutch means in its engaged condition for a predetermined period so as to impart a desired angular stroke to said output shaft, and means operated by said control shaft in timed relation to said period for reversing the direction of output drive of said output shaft.

2. Apparatus as defined by claim 1 wherein the last mentioned means includes a plurality of electrical switching means which are moved to and held in closed condition during the movement of said control shaft through predetermined variable angles of rotation.

3. A drive mechanism; comprising a drive shaft, an output shaft, clutch means operable to rotatably couple said shafts, means for rotatably driving said drive shaft, reversible gear means operably connected to said output shaft, a first control means for maintaining said clutch means in its engaged condition for a predetermined desired period, a seecond control means for operating said reversing mechanism after the termination of said period, and means subsequently causing engagement of said clutch means for a second period that is substantially equal in duration to the first mentioned period.

4. A drive mechanism; comprising a drive shaft, an output shaft, clutch means operable to rotatably couple said shafts, a control shaft, means for driving said drive shaft and said control shaft in timed relation, reversible gear means operatively connected to said output shaft, 21 first control means operated by said control shaft for maintaining said clutch means in engaged condition for a first predetermined period, a second control means for operating said reversible gear means after the termination of said period, and a third control means operable after the operation of said second control means for causing engagement of said clutch means for a second period that is substantially equal in duration to said first period.

5. Apparatus as defined by claim 4; additionally comprising a one revolution clutch operatively disposed between said control shaft and said drive means.

6. A drive mechanism; comprising a drive shaft, an output shaft, clutch means operable to rotatably couple said shafts, electromechanical means for operating said 5 clutch means, drive means for rotating said drive shaft and said control shaft in timed relation, a plurality of timing cams mounted on said control shaft; and a plurality of electrical switches adapted to be respectively operated by said timing cams, said switches being connected to 10 control the actuation of said electromechanical means so as to be capable of maintaining said clutch means in the engaged condition for predetermined periods.

7. Mechanism according to claim 6 including means to condition one or more of said switches for subsequent 15 closure by corresponding timing cams, and means associated with said control shaft to uncondition said switches subsequent to switch closing operation of said cams.

8. Mechanism according to claim 6 wherein said clutch means comprises a wrapped spring clutch and said electromechanical means comprises a solenoid electrically connected to said switches and mechanically associated with said clutch.

9. Apparatus as defined by claim 6'; additionally comprising a reversible gear means operatively connected to said output shaft, and control means operated by said control shaft for operating said reversible gear means.

10. Apparatus as defined by claim 9; wherein each of said timing cams has two lobes thereon which are operatively eifective respectively before and after the operation of said reversing mechanism.

11. Apparatus as defined by claim 10; additionally comprising a one revolution clutch operatively connected between said drive means and said control shaft.

References Cited in the file of this patent UNITED STATES PATENTS 919,006 Hancock Apr. 20, 1909 2,364,147 Jones Dec. 5, 1944 20 2,975,648 Doerries Mar. 21, 1961 

1. A DRIVE MECHANISM; COMPRISING A DRIVE SHAFT, AN OUTPUT SHAFT, CLUTCH MEANS OPERABLE TO COUPLE SAID DRIVE AND OUTPUT SHAFTS, A CONTROL SHAFT, MEANS FOR DRIVING SAID CONTROL AND DRIVE SHAFTS, MEANS OPERATED IN TIMED RELATION TO THE ROTATION OF SAID CONTROL SHAFT FOR MAINTAINING SAID CLUTCH MEANS IN ITS ENGAGED CONDITION FOR A PREDETERMINED PERIOD SO AS TO IMPART A DESIRED ANGULAR STROKE TO SAID OUTPUT SHAFT, AND MEANS OPERATED BY SAID CONTROL SHAFT IN TIMED RELATION TO SAID PERIOD FOR REVERSING THE DIRECTION OF OUTPUT DRIVE OF SAID OUTPUT SHAFT. 